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<a name="1" href="#1">1</a>   <em class="comment">/*</em>
<a name="2" href="#2">2</a>   <em class="comment"> * @(#)Pair.java     28 Aug 2008</em>
<a name="3" href="#3">3</a>   <em class="comment"> * </em>
<a name="4" href="#4">4</a>   <em class="comment"> * Copyright © 2009 Andrew Phillips.</em>
<a name="5" href="#5">5</a>   <em class="comment"> *</em>
<a name="6" href="#6">6</a>   <em class="comment"> * This program is free software: you can redistribute it and/or modify</em>
<a name="7" href="#7">7</a>   <em class="comment"> * it under the terms of the GNU General Public License as published by</em>
<a name="8" href="#8">8</a>   <em class="comment"> * the Free Software Foundation, either version 3 of the License, or</em>
<a name="9" href="#9">9</a>   <em class="comment"> * (at your option) any later version.</em>
<a name="10" href="#10">10</a>  <em class="comment"> *</em>
<a name="11" href="#11">11</a>  <em class="comment"> * This program is distributed in the hope that it will be useful,</em>
<a name="12" href="#12">12</a>  <em class="comment"> * but WITHOUT ANY WARRANTY; without even the implied warranty of</em>
<a name="13" href="#13">13</a>  <em class="comment"> * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the</em>
<a name="14" href="#14">14</a>  <em class="comment"> * GNU General Public License for more details.</em>
<a name="15" href="#15">15</a>  <em class="comment"> *</em>
<a name="16" href="#16">16</a>  <em class="comment"> * You should have received a copy of the GNU General Public License</em>
<a name="17" href="#17">17</a>  <em class="comment"> * along with this program. If not, see &lt;<a href="http://www.gnu.org/licenses/" target="alexandria_uri">http://www.gnu.org/licenses/</a>>.</em>
<a name="18" href="#18">18</a>  <em class="comment"> */</em>
<a name="19" href="#19">19</a>  <strong>package</strong> com.qrmedia.commons.collections;
<a name="20" href="#20">20</a>  
<a name="21" href="#21">21</a>  <strong>import</strong> org.apache.commons.lang.ObjectUtils;
<a name="22" href="#22">22</a>  <strong>import</strong> org.apache.commons.lang.builder.HashCodeBuilder;
<a name="23" href="#23">23</a>  
<a name="24" href="#24">24</a>  <em>/**<em>*</em></em>
<a name="25" href="#25">25</a>  <em> * A pair of objects.</em>
<a name="26" href="#26">26</a>  <em> * </em>
<a name="27" href="#27">27</a>  <em> * @param &lt;U> the type of the first object</em>
<a name="28" href="#28">28</a>  <em> * @param &lt;V> the type of the second object</em>
<a name="29" href="#29">29</a>  <em> * @author anph</em>
<a name="30" href="#30">30</a>  <em> * @since 28 Aug 2008</em>
<a name="31" href="#31">31</a>  <em> *</em>
<a name="32" href="#32">32</a>  <em> */</em>
<a name="33" href="#33">33</a>  <strong>public</strong> <strong>class</strong> Pair&lt;U, V> {
<a name="34" href="#34">34</a>      <strong>protected</strong> <strong>final</strong> U firstObject;
<a name="35" href="#35">35</a>      <strong>protected</strong> <strong>final</strong> V secondObject;
<a name="36" href="#36">36</a>      
<a name="37" href="#37">37</a>      <em>/**<em>*</em></em>
<a name="38" href="#38">38</a>  <em>     * Creates a pair consisting of two objects.</em>
<a name="39" href="#39">39</a>  <em>     * </em>
<a name="40" href="#40">40</a>  <em>     * @param firstObject    the first object of the pair</em>
<a name="41" href="#41">41</a>  <em>     * @param secondObject  the second object of the pair</em>
<a name="42" href="#42">42</a>  <em>     */</em>
<a name="43" href="#43">43</a>      <strong>public</strong> <a href="../../../../com/qrmedia/commons/collections/Pair.html">Pair</a>(U firstObject, V secondObject) {
<a name="44" href="#44">44</a>          <strong>this</strong>.firstObject = firstObject;
<a name="45" href="#45">45</a>          <strong>this</strong>.secondObject = secondObject;
<a name="46" href="#46">46</a>      } 
<a name="47" href="#47">47</a>  
<a name="48" href="#48">48</a>      <em class="comment">/*<em class="comment"> copy "constructors" */</em></em>
<a name="49" href="#49">49</a>      
<a name="50" href="#50">50</a>      <em>/**<em>*</em></em>
<a name="51" href="#51">51</a>  <em>     * Creates a copy of this pair.</em>
<a name="52" href="#52">52</a>  <em>     *</em>
<a name="53" href="#53">53</a>  <em>     * @return a copy of this pair</em>
<a name="54" href="#54">54</a>  <em>     */</em>
<a name="55" href="#55">55</a>      <strong>public</strong> Pair&lt;U, V> copy() {
<a name="56" href="#56">56</a>          <strong>return</strong> <strong>new</strong> Pair&lt;U, V>(firstObject, secondObject);
<a name="57" href="#57">57</a>      }
<a name="58" href="#58">58</a>  
<a name="59" href="#59">59</a>      <em>/**<em>*</em></em>
<a name="60" href="#60">60</a>  <em>     * Creates a pair using the second object of this pair and the</em>
<a name="61" href="#61">61</a>  <em>     * new first object.</em>
<a name="62" href="#62">62</a>  <em>     * </em>
<a name="63" href="#63">63</a>  <em>     * @param newFirstObject the new first object</em>
<a name="64" href="#64">64</a>  <em>     * @return a pair consisting of the new first object and the second object of this</em>
<a name="65" href="#65">65</a>  <em>     *  pair</em>
<a name="66" href="#66">66</a>  <em>     */</em>
<a name="67" href="#67">67</a>      <strong>public</strong> Pair&lt;U, V> copyKeepSecond(U newFirstObject) {
<a name="68" href="#68">68</a>          <strong>return</strong> <strong>new</strong> Pair&lt;U, V>(<strong>new</strong>FirstObject, secondObject);
<a name="69" href="#69">69</a>      }
<a name="70" href="#70">70</a>  
<a name="71" href="#71">71</a>      <em>/**<em>*</em></em>
<a name="72" href="#72">72</a>  <em>     * Creates a pair using the first object of this pair and the</em>
<a name="73" href="#73">73</a>  <em>     * new second object.</em>
<a name="74" href="#74">74</a>  <em>     * </em>
<a name="75" href="#75">75</a>  <em>     * @param newSecondObject the new second object</em>
<a name="76" href="#76">76</a>  <em>     * @return a pair consisting of the first object of this pair and the new second</em>
<a name="77" href="#77">77</a>  <em>     *  object</em>
<a name="78" href="#78">78</a>  <em>     */</em>
<a name="79" href="#79">79</a>      <strong>public</strong> Pair&lt;U, V> copyKeepFirst(V newSecondObject) {
<a name="80" href="#80">80</a>          <strong>return</strong> <strong>new</strong> Pair&lt;U, V>(firstObject, <strong>new</strong>SecondObject);
<a name="81" href="#81">81</a>      }
<a name="82" href="#82">82</a>      
<a name="83" href="#83">83</a>      <em class="comment">/*<em class="comment"> (non-Javadoc)</em></em>
<a name="84" href="#84">84</a>  <em class="comment">     * @see java.lang.Object#equals(java.lang.Object)</em>
<a name="85" href="#85">85</a>  <em class="comment">     */</em>
<a name="86" href="#86">86</a>      @Override
<a name="87" href="#87">87</a>      <strong>public</strong> <strong>boolean</strong> equals(Object obj) {
<a name="88" href="#88">88</a>          
<a name="89" href="#89">89</a>          <strong>if</strong> (<strong>this</strong> == obj) {
<a name="90" href="#90">90</a>              <strong>return</strong> <strong>true</strong>;
<a name="91" href="#91">91</a>          }
<a name="92" href="#92">92</a>  
<a name="93" href="#93">93</a>          <strong>if</strong> (!(obj instanceof Pair)) {
<a name="94" href="#94">94</a>              <strong>return</strong> false;
<a name="95" href="#95">95</a>          }
<a name="96" href="#96">96</a>  
<a name="97" href="#97">97</a>          Pair&lt;?, ?> other = (Pair&lt;?, ?>) obj;
<a name="98" href="#98">98</a>          
<a name="99" href="#99">99</a>          <em class="comment">// the pair is *not* ordered!</em>
<a name="100" href="#100">100</a>         <strong>return</strong> ((ObjectUtils.equals(firstObject, other.firstObject) 
<a name="101" href="#101">101</a>                  &amp;&amp; ObjectUtils.equals(secondObject, other.secondObject))
<a name="102" href="#102">102</a>                 || (ObjectUtils.equals(firstObject, other.secondObject) 
<a name="103" href="#103">103</a>                     &amp;&amp; ObjectUtils.equals(secondObject, other.firstObject)));
<a name="104" href="#104">104</a>     }
<a name="105" href="#105">105</a> 
<a name="106" href="#106">106</a>     <em class="comment">/*<em class="comment"> (non-Javadoc)</em></em>
<a name="107" href="#107">107</a> <em class="comment">     * @see java.lang.Object#hashCode()</em>
<a name="108" href="#108">108</a> <em class="comment">     */</em>
<a name="109" href="#109">109</a>     @Override
<a name="110" href="#110">110</a>     <strong>public</strong> <strong>int</strong> hashCode() {
<a name="111" href="#111">111</a>         
<a name="112" href="#112">112</a>         <em class="comment">// HashCodeBuilder is order-sensitive, so the objects of the pair must be "ordered" too</em>
<a name="113" href="#113">113</a>         <strong>boolean</strong> firstObjectHashCodeGreater = (hashCode(firstObject) > hashCode(secondObject));
<a name="114" href="#114">114</a>         <strong>return</strong> <strong>new</strong> HashCodeBuilder()        
<a name="115" href="#115">115</a>                .append(firstObjectHashCodeGreater ? firstObject : secondObject)
<a name="116" href="#116">116</a>                .append(firstObjectHashCodeGreater ? secondObject : firstObject).toHashCode();
<a name="117" href="#117">117</a>     }
<a name="118" href="#118">118</a>     
<a name="119" href="#119">119</a>     <strong>private</strong> <strong>int</strong> hashCode(Object object) {
<a name="120" href="#120">120</a>         <strong>return</strong> ((object != <strong>null</strong>) ? object.hashCode() : 0);
<a name="121" href="#121">121</a>     }
<a name="122" href="#122">122</a> 
<a name="123" href="#123">123</a>     <em class="comment">/*<em class="comment"> (non-Javadoc)</em></em>
<a name="124" href="#124">124</a> <em class="comment">     * @see java.lang.Object#toString()</em>
<a name="125" href="#125">125</a> <em class="comment">     */</em>
<a name="126" href="#126">126</a>     @Override
<a name="127" href="#127">127</a>     <strong>public</strong> String toString() {
<a name="128" href="#128">128</a>         <strong>return</strong> <span class="string">"{"</span> + getPairStringRepresentation() + <span class="string">"}"</span>;
<a name="129" href="#129">129</a>     }
<a name="130" href="#130">130</a>     
<a name="131" href="#131">131</a>     <strong>protected</strong> String getPairStringRepresentation() {
<a name="132" href="#132">132</a>         
<a name="133" href="#133">133</a>         <em class="comment">// Doh! *Why* is this (String) cast necessary??</em>
<a name="134" href="#134">134</a>         <strong>return</strong> toString(firstObject) + <span class="string">", "</span> + toString(secondObject);
<a name="135" href="#135">135</a>     }
<a name="136" href="#136">136</a>     
<a name="137" href="#137">137</a>     <strong>private</strong> String toString(Object object) {
<a name="138" href="#138">138</a>         <strong>return</strong> ((object != <strong>null</strong>) ? object.toString() : <span class="string">"null"</span>);
<a name="139" href="#139">139</a>     }
<a name="140" href="#140">140</a> 
<a name="141" href="#141">141</a>     <em class="comment">/*<em class="comment"> Getter(s) and setter(s) */</em></em>
<a name="142" href="#142">142</a> 
<a name="143" href="#143">143</a>     <em>/**<em>*</em></em>
<a name="144" href="#144">144</a> <em>     * Getter for firstObject.</em>
<a name="145" href="#145">145</a> <em>     *</em>
<a name="146" href="#146">146</a> <em>     * @return the firstObject.</em>
<a name="147" href="#147">147</a> <em>     */</em>
<a name="148" href="#148">148</a>     <strong>public</strong> U getFirstObject() {
<a name="149" href="#149">149</a>         <strong>return</strong> firstObject;
<a name="150" href="#150">150</a>     }
<a name="151" href="#151">151</a> 
<a name="152" href="#152">152</a>     <em>/**<em>*</em></em>
<a name="153" href="#153">153</a> <em>     * Getter for secondObject.</em>
<a name="154" href="#154">154</a> <em>     *</em>
<a name="155" href="#155">155</a> <em>     * @return the secondObject.</em>
<a name="156" href="#156">156</a> <em>     */</em>
<a name="157" href="#157">157</a>     <strong>public</strong> V getSecondObject() {
<a name="158" href="#158">158</a>         <strong>return</strong> secondObject;
<a name="159" href="#159">159</a>     }
<a name="160" href="#160">160</a>     
<a name="161" href="#161">161</a> }
</pre>
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